Aircraft launched flares are used for purposes such as illumination, signaling, marking, decoy countermeasures and the like. Decoy flares conventionally comprise a hot-burning composite material which is formed into a desired shape. The shape generally corresponds to the shape of the storage container or dispenser can from which the flare is ejected by the aircraft. A variety of cross-sectional shapes are used, for example, flares generally have a circular, square, or rectangular cross-section.
A number of heat seeking missiles have seekers that incorporate rate biased counter-countermeasures which reject decoys not exhibiting forward motion relative to the targeted aircraft. Missile rich theaters of military operation have lead to initiatives to increase the effectiveness of infrared decoy flares deployed from aircraft. In the area of countermeasures, flares are now designed to defeat the most sophisticated heat-seeking missiles.
Unlike standard decoy flares which are dropped from aircraft like “hot bricks”, certain infrared flare countermeasure devices are designed to fly a predetermined trajectory alongside an aircraft. One method employed in countermeasures to mimic aircraft trajectory is to replace the conventional open burning decoy flare with a kinematic (or self propelled) flare. While kinematic flares are most suitable for high speed and high altitude applications, in low altitude and slow applications, a kinematic flare would have a lower IR output than an open burning flare.
Another method is to fire or launch the flares in a forward direction. To facilitate this method, a weighted nose is added to the standard flare design to improve the flare's forward fired ballistic performance. This relatively simple low cost improvement increases the distance the flare flies in the forward direction and improves effectiveness by providing enhanced decoy trajectory. It also reduces the size of the dispersion cone of the flare allowing the flare dispensers to be aimed in a more forward and upward direction for further improved effectiveness of the entire flare suite. Flares with ballistic nose weights travel approximately twice as far before burnout as do standard flares. Nose weights are used with both kinematic and standard flares.
Current standard flare containers are usually a cylindrical, square, or rectangular cartridge case, open at one end. The flare is built-up in the cartridge case, optionally including a nose weight at the front, or open end of the cartridge case. The nose weight is typically a solid metal weight comprised of, for example, brass, steel, tungsten alloy, or sintered tungsten. If employed, the nose weight is fixed securely into position, lest it come loose and interrupt the flight-path of the flare. As related later, the inclusion of the nose weight poses a potentially damaging event due to the potential for, after the propulsion is expended, the falling flare nose to strike ground personnel, equipment or buildings or be ingested into aircraft engines of aircraft operating in the combat area. This is an emerging issue as weighted nose flares have been deployed in increasing numbers in recent years and heat seeking missiles are now being employed against an attacking helicopter assault, which may include advancing ground forces. The shoulder fired heat seeking missile has become a great threat to low flying aircraft in these types of operations. Spent noses from decoy flares can be ingested by aircraft engines, i.e. helicopter engines, causing catastrophic failure, and ultimately causing the aircraft to crash. The possibility of a spent metal nose getting into the intake of an adjacent aircraft's engine and damaging its turbine blades also exists on kinematic decoy flares with weighted noses. Likewise, the falling nose from that high altitude has the potential to cause great damage to personnel, civilians, equipment or buildings on the ground.
Earlier standard designs utilize decoy flares without nose weights; however these are generally of significantly inferior performance since the trajectory disintegrates as the propulsion cartridge burns and the center of gravity and internal inertia shift and diminish. Accordingly the inclusion of a nose weight is considered an important inclusion. The benefit of inclusion of the nose weighted flare is that when forward fired, the flare will travel approximately twice as far prior to burn-out. This is attributed to the shifting of the center of gravity of the flare forward which keeps it from tumbling. The significance of the enhanced forward travel of the flare is its increased likelihood of attracting the rate-biased infrared missile seekers as the flare remains in flight as a target for a longer period.
The present invention includes a weighted nose through the inclusion of a thin walled nose cup which is filled with a high-density metal powder which will dump at the end of the propellant burn and render the residual of the nose weight harmless to adjacent aircraft and personnel and material on the ground.
It is an objective of the present invention to avoid the FOD problems associated with the classic solid metal weighted nose flare designs by utilizing a thin walled cup filled with high-density metal powder as a ballistic weight to mass stabilize the flare. Because the metal powder dumps from the nose cup once the flare has burned out leaving the very light weight nose cup as the only residual solid object, the present invention virtually eliminates the possibility of FOD. Another objective of the present invention is to create a nose weight design that is lower in cost than one utilizing a machined metallic forward closure.